1. Field of the Invention
The present invention relates to an optical unit applied to image pickup equipment and an image pickup apparatus.
2. Description of the Related Art
In recent years, image pickup equipment mounted on a mobile phone, a personal computer (PC), or the like has been asked to realize a high resolution, a low cost, and miniaturization.
An image sensor, such as a CCD (charge coupled device) and a CMOS (complementary metal oxide semiconductor) image sensor, has a remarkably reduced cell pitch. Thus, an optical system is required to have such a high image-forming performance that an optical aberration, particularly, an axial chromatic aberration is further suppressed as compared to a normal optical system.
There are now many cases where high-end models of mobile phones use an optical system with the structure of four elements in four groups.
With a recent increase in number of pixels, even the aforementioned structure provides inadequate performance.
In view of this, it is necessary to study the structure of five elements in five groups.